Sustainable energy and innovation are one of the highest priority items of present modern societies. Here, solar energy and wind power are important, as well as the electrification cars. When looking at the overall image, the modern society must become more electrified to overcome issues with, among others, air pollution and global warming.
This electrification will require high-performance power converters to allow for example electric cars to charge, solar panels and windmills to deliver energy to the grid, and electric motors to operate. All of these generate or consume a large amount of power. In case of the electric car battery charger and the electric motor, power can flow in both directions: regenerating kinetic energy to electric power while braking and degenerating electric energy to kinetic energy while accelerating. To ensure safety and low leakage currents, isolation between energy sources can be desired.
Current state-of-the-art AC/DC converters for such applications require a large amount of inductive energy storage and often have a two-stage design with an intermediate high-voltage bus. This high-voltage bus increases the voltage rating of the devices and requires a high voltage-rating for the bus capacitance. Furthermore, balancing the power flow between both stages can be problematic.